Study to determine if a 5-day fast will increase spontaneous pulsatile GH secretion as well as the response to the synthetic hexapeptide GH-releasing peptide (GHRP) in obese (more than 150 percent ideal body weight) subjects. EEG monitoring during sleep will also be performed to determine if the normal relationship between delta sleep and GH secretion is altered in obesity. COMPUTER & CORE LAB ONLY.